Tool holdeb fob metal-wobxing machines



Ulft. 2l, 1930. w BURKART ET AL 1,779,059

TOOL HOLDER FOR METAL WORKING MACHINES Filed Mann 14, 1929 Patented oef. 21, 1930 l i UNITED Asiyrrlezs PATENT; ovl-"ifIca( 'WILLIAM BUBKABT FRANK H. PETEBSEN, OF DENVER, COLQBADO l TOOL HOLDER FOB METAL-WORKING MACHINES application mea umh i4, 1929. serial no. 346,830.-

Our invention relates to improvements in tool holders for metal-working machines, and more particularly to holders for use in connection with steel tools of maximum hardness.

The primary obj ect of the invention is to provide a holder in which the tool is held and su orted at every point so that it will not be su Jected touneven strain or pressure, or to vibratory action withinthe holder, when in use, thereby eliminating the probability of its being broken. A

Further, to provide a holder in which the tool is held by clampinghpressure which is exerted uniformly throng out the length of the tool along its sides, and in which the cutting end of the tool is supported to withstand the vertical strain exerted against its cutting ed e.

igt further object of the invention is to provide a holder with improved means for feeding the tool forward therein, as the length of the tool is diminished by wear, and consequent sharpening, and for supporting the tool against inward movement.

inafter appear are accomplished by the device illustrated in the accompanying drawin s vin which,

igure 1 is a side view of a portion of a metal-working lathe showing the improved tool holder in connection therewith. 4 n

Figure 2 is a vertical longitudinal sectional view--full size-through the improved tool holder showing the tool therein and the 1mproved mechanism for pushing the tool forward and supporting the same against backward movement.

Figure 3 is a horizontal sectional view of the holder on the line 3-3 of Figure 2, the tool and the means for pushing the same forward being removed. Y

Figure 4 is'a transverse sectional view of the holder on the line 4 4 of Figure 2.A

Figure 5 is a vsectional View thereof on the line 5-5 of Figure2.

Figure is a side view of a portion of the main or body member of the holder, the bar which forms l.the other member being re moved.

These, vand other objects which will here-l Fi ure 7 is a sectional view `of the saine on the line 7--7` of Figure 6.

Figure 8 is a erspective view of a portion of the bar whicli forms the other member of the holder. 55

v Figure 9 is an end view of the threaded plug forming part of the tool adjusting mech,- anism, and

Figure 10 is a view of an implement for turning the threaded plug. 60

`Our improved tool holder is adapted to hold metal-cutting tools of the hardest character of steel, for use in lathes, planers, shapers, boring-mills and other metal-cutting machines; and our tool holder has been especially invented to hold a German-made steel called Widia. Tool steel of this name and character is so brittle thati when used in the common type of tool post it fre uently breaks under the clamping pressure o? the set screw 7 in the tool post, for the reason that the clamping pressure under which it is held it not uniformly distributed. In the common type of holder, the tool is inserted in a square hole in the tool-post and is clamped tight-lythe'rein 75 i by a set screw, and the tool is under greatest pressure at the point where the sety screw is turned down against it, and should there be the slightest unevenness either in the bottom of the hole or in the tool, the tool will snap and break into two pieces under the clamping strain at the set screw and the cutting at the cutting edge of the tool. Our improved holder eliminates the probability of reakage by providing an improved manner \95 of clamping the tool, as will now be particularly described.

Referring to the accompanying drawings The numeral l refers generally to a metall l working lathe, provided with,l carriage 2, Aa compound rest', a tool post 4, anda cross feed` screw 5, all of which parts are of common construction andtherefore constitute no part of the present invention. n

The letter A designates the im roved tool holder, which comprises two mem ers,"B and C. The member B constitutes theymain or body portion of the'holder and is preferably about eight inches long, about one inch and ve-eighths wide, and about three-quarters of 10 aninch thick. The bodis channeled for about three-fourths of its ength from its for- `ward end, as shown at 6, and the bottom of 'the channel terminates at its rear end in an outwardly curved face 7. The member C of the holder is in the form of a bar which lits snugly within the' channel 6 and its rear end is curved as s hown at 8 t-o correspond to the through the forwardend of the block. The

groove 9--10 is square throughout, and preferabl three-eighths of an inch 1n diameter, and the part 10 of the groove receives the tool D. The forward end of the lower side of the groove 1() extends slightly beyond the bottom thereof, as shown at 11, thisextenslon forming a support for the under side of the pro- 'ectin end of the tool, as will be understood y re lerence to Figure 2.

A round hole 12 isformed 1n the rear end of the body member B and extends -through to the channel 6 in said member and in axial line\with the groove 9 in the bar C, and thls holelis tapped to form an internal thread onehalf) inch in diameter. Ordinarily, this threaded hole 12 would extend through the' curved face 7 of the channel, thereby forming .a series of incomplete threads which would'serve no'purpose. To obviate th1s, a

hole 13 is drilled into the curved face 7 at right angles to the axis of the/threaded .hole 12, as shown by the dotted circle, thus forming a straight wall 14 at the rear end of the channel 6, through which the threaded hole 12 passes, as will be understood by reference to Figure 6.` The bottom of the hole 13 1s reamed out, so as to be on a level with the bottom of the channel 6. The tool D comprises a bar eighths of an inch square, and its cutting end lmay be half round or any vother required shape. The tool is inserted in the inclined groove 10, and in order to insure a umform support of the tool along its lower and righthand sides, which are the sidessubjected to 'strain or pressure under cutting action; an

angle plate 15 of thin sheet copper isdisposed along the bottom and right-hand sides of the tool, as shown in Figures -2 and 5, and this angle late inl a manner cushlons the straln upon t ese sides of the tool, and absorbs any possible vibratory action. The side member of the copper plate contacts with the bottom face of the channel 6 of the body member B of .steel about t'wo and one-half inches long and three-A and clamping pressure of the body B and bar C upon the tool is effected by a bolt 16 which passes loosel through a hole in the bod member and into a threaded hole in the bar (l: the head of the bolt being forcibly turned against the body, thereby clamping'the tool between the two parts of the holder. By this means the tool is held under/a uniform clamping pressure throughout its length. The curved end portion 8 of the bar is preferably electrically welded to the body member although it may be riveted or otherwise secured thereto, thereby becoming practically an integral part of it, and this arrangement not only secures the bar to the body, but permits a sulicient yielding movement of the rcmailling portion of the bar within the channel 6 tofadmit of the clamping action above described.

As the length of the tool is diminished by wear and consequent sharpening, it is moved forward and supported in the groove 10, against backward thrust, in the following manner A rod or plunger 17 is inserted in the threaded hole 12 and into the groove 9 of the bar C. This plunger is of a length to extend from a short distance from the entrance of the hole 12 to a point about one-half of the length of the roove 9, and between the front l end of this p unger and the rear end of the tool are interposed a number of hard steel balls 18. A threaded plug 19 is screwed into the hole 12 against the plunger rod .17 by i means of a crank rod 20 having a squared end 21 which enters a square socket 22 in the said plug, or the plug may be turned by an ordinary screw driver, the end of'which, when inserted in the socket 22, will engage two diavonally opposite corners of the said socket,V By this arrangement, the plunger `rod 17 can be screwed forward as the tool diminishes in length, until the forward end of the rod enfor gages the inclined face of the groove 10 duri ing which movement ofthe rod the balls 18 `will pass from the groove 9 into the roove 10, thereby holding the tool aganst bac Ward movement in the holder until the said tool is too short for further use.,

In order to prevent the balls from rolling out of the holder when the tool is removed for sharpening or for the insertion of a different tool, a hole 23 is drilled into the bottom edge of the bar C, at right angles to and in line with the groove 10. A drill having a roundved cutting point is used for this purpose, and

when .the point of the drill pierces the wall of the slot 10, the drilling is stopped, thus leaving a holevin'the wall of the slot l() of less diameter than the hole 23, Vthus providing a shoulder 24 in the bottom of the said hole 23. A ball 25 is inserted in the hole 23,' a coil spring 26 is then placed in the hole against the ball, and the spring is heldunder coinpression by a disk 27, which is screwed into I the'entrance o f the hole against 'the spring,

ool

the outrance portiou'of the hole being threadcd. When the tool Dis removed, the spring 2o will force the ball .25 against the bottom of the hole 23, and the ball will ro'ect slightly into the groove 10, but the s ioulder 24 will limit its further movement. The. projecting part of the ball will thus form a barrier in the slot 10 which will reveut the balls 18 from rolling out of the older.

B the improved ty e of tool holder herein set forth, the tool is c amped under uniform pressure throughout its length; the thin copper angle plate contributing to this end, and acting to absorbany posible vibration in the tool, and the balls interposed between the plunger rod 17 and the rear end of the tool, act to translate the horizontal thrust of the plunger rod into a thrust in the direction of the angle of the drill, so that the tool is not only held against back thrust, but can be moved forward in the inclined groove until it is too short for further use.

As the bar C is Welded at one end to the body member B, it is inseparable therefrom, and therefore the balls 18 must be inserted iu the holder through the threaded hole 12, and the balls are of a size to i'it snugly but slidably in the groove 9 of the bar, which is closed on one side by the wall of the body member, as clearly shown in Figures 4 and 5.

In operation, the holder is clamped in the tool post of the machine in theusual manner, the tool is placed in the groove 10 of the holder, and the threaded plug 19 is adjusted so that the plunger rod 17 and balls 18 will support the tool in the required position; the tool is then ready for use.

`Having described our invention, what we claim as new and desire to secure by Letters Patent, is

1. A tool holder of the character described comprising a body member channeled for the greater part of its length, the unchanneled portion having a longitudinal threaded hole therein; a barin said channel having a horizontal grogye in axial line with said threaded hole, which terminates in an upwardly inclined tool receiving groove; a tool therein; means for clamping the body member and bar upon said tool to hold the same in place; a push rod in said threaded hole and extending into the groove in said bar; a threaded plug in the threaded hole for moving the rod forward and holding the same against back thrust; and balls interposed between the rod and the rear end of the tool, to translate the horizontal thrust of the rod into an angular thrust in line with the axis of the tool.

2. A tool holder of the character described, comprising a body member channeled for the greater part of itslength, the unchanneled portion thereof having a threaded longitudinal hole; a bar in said channel havlng a horizontal groove in line withl the threaded ,body member and is in threat ed engagement withthe bar, for clamping the parts against the tool, thereby to hold the same in place;

a push rod Adisposed in the threaded hole and in the horizontal groove; a threaded plug in the hole for moving the rod forward and holding the same against back thrust, and a series of contacting elements between the rod and the rear end of the tool, whereby the horizontal thrust in therod is translated into an angular thrust upon the tool in line with its axis as the same is moved forward in its groove, said bar being welded at its rear end portion to the body member.

3. In a tool holder of the character described, a member channeled for the greater part of its length; a bar in the channel, its rear end portion being Welded to the channeled member, the unchanneled portion of the member having a threaded longitudinal hole therein and the bar having a horizontal groove in line with the hole, t-he forward portion of which terminates in an upwardly inclined tool holding groove, a tool in said groove, a push rod disposed in the threaded hole and horizontal groove, a threaded plug in the hole for moving the rod forward and holding the same against back thrust; balls interposed bet-Ween the rod and the rear end of the tool, to impart the horizontal thrust of the rod to the tool as the same is moved forward in its groove; means for clamping the channeled member and bar upon the tool to hold the same, said bar having a socket therein at right angles to the inclined groove, said socket having a hole in its bottom opening through the adjacent wall of the inclined groove, and of less diameter than the socket; and a spring-actuated ball in the socket, which projects through the hole in the bottom of the socket when the tool is removed, thereby to present a barrier in the inclined groove to prevent the escape of first mentioned balls from the holder.

4. A tool holder of the character described comprising a body channeled for a portion of its length; a bar in said channel, the rear end portion of which is Welded to said body, the remaining portion being free, a groove being formed in said bar, registering at one end with a threaded hole in the body, the other end portion of the groove being upwardly inclined and constituting a tool-receiving groove; a tool in said groove, the metal forming the lower side of the tool-receiving groove being extended bevond the entrance to said groove to form a support for the cutting end of the tool; a thin copper angle plate disposed along the bottom and one side of said tool; a clamp bolt extending loosely through the forward end of the body and in threaded engagement with the bar' for clamping the parts upon the said tool; a rod disposed in the threaded hole and in 5 the adjoining portion of the groove; means threaded in the -hole for movin the rod and holding the same against back t rust; means interposed between the end of the rod and thetool for transmitting the thrust of the rod to the tool in line with its axis.

In testimony whereof, We afiix our signatures.

WILLIAM BURKART. FRANK H. PETERSEN. 

